The present invention relates to a new and improved construction of a spindle extension, especially for drilling and milling machines, which contain a spindle with an automatic tool chucking or clamping device. The automatic tool chucking device contains a chucking clamp or clamping element. There is also provided a spindle extension piece or element which can be inserted into an inner cone or conical portion of the spindle and has an inner cone or conical portion for the reception of a tool cone of a tool.
There are known to the art spindle extensions for drilling and milling machines, wherein the tool is retained by means of threaded bolts or screws and no longer can be held by the automatic tool chucking or clamping mechanism, or wherein an elongated chucking or clamping pin must be attached to the tool, so that there can be used the automatic chucking or clamping device.
Different constructions of tool clamping devices are known to the art, for instance, from U.S. Pat. Nos. 3,177,775, 3,762,271, 3,797,956, 4,122,755, French Pat. Nos. 1,451,525, 1,452,753, 2,288,579, German Pat. No. 578,974 and the German language publication "Werkstatt und Betrieb", 109 (1976)10, the article entitled "Zeitgemasse Konzeption einer vertikalen Bohr und Frasmaschine", appearing at pages 555 to 558.